The brain works on the sixth floor of building BG2 at Frankfurt Airport. Light-gray carpet, flat screens on the walls, desks encircled by up to nine monitors. The brain works silently and with the utmost concentration amid muted human murmurings.

The brain monitors roughly 40 million passengers a year,28 million transfers, 15 000 flight attendants, 4000 pilots and 183 aircraft. It keeps an eye on the winds over the Atlantic, blizzards in southern Germany, potential volcanic eruptions in Mexico – and it ensures that roughly 11 500 tons of kerosene a day gush into the aircraft tanks at the right time.

Every day, Frankfurt Airport handles some 800 Lufthansa flights from all over the world, and that means high air-traffic-control fees – and every mistake costs money. There are always at least 35 pilots and 100 flight attendants on stand-by; and every day, 1300 cockpit crews and 4200 cabin staff fly to 172 destinations. Myriad numbers, countless processes, so many people: The brain coordinates them all.

The brain, Lufthansa’s nerve center in Frankfurt, has a name: IOCC, Integrated Operation Control Center. Around 400 people work here, controling the airline’s global flight movements from and to Frankfurt and on the ground.

Snippets of conversation flit around the open-plan office. “Singapore, good weather.” “Denver rerouting to Montreal due to a medical emergency.” “No irregs so far.” Irregs are irregularities, and they are anathema to the brain. The control center responds by switching up a notch.

Irregs are an everyday occurrence. A storm over Detroit, an air-traffic-control strike in France, a delayed flight from South America – any of these can disrupt the complex network of processes, triggering all manner of snowball effects.

That’s why a team of Lufthansa experts works 24/7 to take action and bring things back to normal as fast as possible, always with a plan B up their sleeve, anticipating problems and finding speedy solutions.

Gerrit Klempert, 47, heads the IOCC team responsible for ground operations at Frankfurt Airport. “We need to adjust parameters here and there, pull the right levers at the right time,” he explains. Sounds easy – and is anything but.

Depending on the type and scale of the irreg, his team has to intervene in highly complex processes. Transfer Coordination, Customer Disposition, Crew Bus Operation. The departments work together to make up for delays. They reduce ground times, prioritize flights, allocate the best parking positions.

New questions keep popping up. How many passengers need to be rebooked to Tokyo, Rio and Munich if the flights from Hamburg, Moscow and New York are delayed? How do we control passenger streams? How can we speed up cleaning and catering? Do we need a ramp direct service to take passengers straight from one aircraft to the next? And when exactly is that storm from southern Hesse expected to blow across the apron?

“All areas are parts of the process,” says team leader Klempert, “everything merges.” The problems start if this gigantic structure wobbles. A glimpse at the screen gives an impression of just how complex it all is. Charts, graphics, status reports, percentages, curves, abbreviations. All across Europe, the world. When there are millions of euros and the itineraries of thousands of passengers at stake, you need nerves of steel and experience by the bucketload.

Klempert remains calm. A doctor of math, he has researched waiting-line theory and congestion logics, and conducted capacity analyses at airports. He lives and breathes stochastic processes and conditional probabilities. Adjust a few parameters and pull the correct lever …

It also takes more than complicated processes to worry Christian Pöselt, 44, a doctor of physics. At IOCC, he heads the department responsible for all flight processes: His staff prepare timetables and check routes, calculate minimum fuel requirements, monitor flight operations, provide pilots with the latest information and change crews.

They sit in front of weather charts, follow flight routes, inquire about short cuts in airspace, and communicate with pilots, directing them if they need to fly around a large storm cell over the equator. They have all the aircraft data on screen in front of them; flying altitude, fuel, speed, course.

They all have one job to do: avoid delays, smooth out irregs and their effects as quickly as possible and keep costs low. “In aviation, every minute costs money,” says Pöselt, “but safety always comes first.”

In aviation, every minute costs money, but safety always comes first

Christian Pöselt, IOCC

Today, as usual, there’s a problem: LH 729 left Shanghai late due to bad weather and is two-and-a-half hours behind its scheduled arrival time. This has a knock-on effect: If the A380 arrives late, can it make the turnaround to Singapore the same evening? It could be a close thing as the night flight ban requires the last plane to be in the air by 23:00.

How many passengers have booked connecting flights? Are there any free hotel rooms if they cannot continue today? The IOCC requests a route through Russian airspace where the winds are more favorable and asks the captain how fast he can fly without using too much kerosene as LH 729 would otherwise only make it to Berlin.

By 18:00 the experts of both teams have come up with measures to get the plane in the air as efficiently as possible. They’ve organized a good apron position so that the passengers can embark and disembark quickly. Larger cleaning and catering teams have been requested, and the new cabin crew has been in- formed. As a precaution, 130 hotel rooms have been reserved.

The brain has gone silent. A brief meeting, everyone is focused on LH 729. Tense faces despite the routine. Can they stop the domino effect and send the same Airbus back to Singapore this evening? If not, things could get expensive for the airline – and cost more than 500 passengers at least ten hours.

“One tiny pebble can trigger an avalanche,” says Klempert, “and that’s something we want to avoid.” His face betrays nothing. Over Russia, going flat out and with a tailwind, the A380 managed to catch up half an hour and has now landed and is parked on the apron; the passengers disembark, the cleaning team boards.

One after another, the colored fields turn green. The teams have turned around the flight as fast as they could: LH 729 becomes LH 778 and takes off for Singapore at 22:45, comfortably before the night flight deadline.

“It’s like standing in a supermarket line just before closing time,” says Klempert, “only you don’t have all these handy levers to flip.” Today, the brain beat the clock and won the game.